ajax 失焦点局部刷新 判断是否存在

jsp代码

<input type="text" name="productname" id="productname" value="" onblur="javascript:myCheck()"/>

 

js 代码

var xmlHttp = newXMLHttpRequest();    

function newXMLHttpRequest() {     

          var xmlreq;    

          if (window.XMLHttpRequest) {     

                xmlreq = new XMLHttpRequest();    

          } else if (window.ActiveXObject) {      

          try {      

                 xmlreq = new ActiveXObject("Msxml2.XMLHTTP");      

          } catch(e1) {      

          try {        

               xmlreq = new ActiveXObject("Microsoft.XMLHTTP");       

          } catch(e2) {}      

      }    

}    

 return xmlreq;   

}

   //检查_入口    

function myCheck(){     

        var name = $("#productname").val();    

        if(name == "" || name == null ){            

            alert("名不能为空");                      

            document.forms['giftdetailform'].productname.focus();           

       }else{       

             var url='giftDetail.do?method=checkName&productname='+encodeURI(name);       

             xmlHttp.open("GET", url);         

             xmlHttp.onreadystatechange = checkName; //回调函数         

             xmlHttp.send(null);      

        }    

}    

//检查_ajax方法    

function checkName(){   

         if (xmlHttp.readyState == 4) {      

              if (xmlHttp.status == 200) {       

                     var json = eval("(" + xmlHttp.responseText + ")");       

                      if(json.res == 1){       

                               alert("名已经存在");       

                               document.forms['giftdetailform'].productname.focus();          

                     }      

              }    

       }    

}

 

Action 方法

 

public ActionForward checkName(ActionMapping mapping, ActionForm form,
   HttpServletRequest request, HttpServletResponse response) throws Exception{
 　　 response.setContentType("application/json");// 设置返回数据类型为xml格式
  　　response.setCharacterEncoding("utf-8");
 　　 PrintWriter out = response.getWriter();
 　　 StringBuffer buf = new StringBuffer();
 　　 JSONObject jsonResult = new JSONObject();
 　　 String name = request.getParameter("productname");
　　  List<GiftDetailForm> listgdf = giftDetailManager.findByName(name.trim());// 查询方法
 　　 if (listgdf.isEmpty()) {
  　　　　 buf.append(0);
  　　}else{
 　　　　  buf.append(1);
 　　 }
 　　 jsonResult.put("res",buf.toString());
  　　out.print(jsonResult.toString());
 　　 out.close();
 　　 return null;
 }